Abstract
The formation of mineral scale has been a major constraint in the oilfield operations as it leads to numerous flow assurance issues. Scale deposition in the formation and production tubing can restrict the flow of hydrocarbon and interferes with the running and operation of downhole equipment. Scale inhibition squeeze treatment is one of the most common form of scale prevention. Although current squeeze treatment is the optimal way to prevent scale from depositing, it is still lack in certain aspect such as adsorption ability and retention time within the rock formation. This paper presents promising advantages of engaging nanotechnology to enhance current scale inhibition treatment. Experimental studies were carried out to examine the potential benefits of using graphene oxide and carbon nanotubes to increase the adsorption of conventional scale inhibitor, ethylenediaminetetraacetic acid (EDTA) on rock formation in a process called nano-carbon enhanced squeeze treatment (NCEST). This process involves treating the rock surface in the near wellbore region with nanomaterials that allow better adsorption capacity of scale inhibitor. Analysis testing using various techniques including field-emission scanning electron microscopy, energy-dispersive X-ray and ultraviolet–visible spectrophotometer were conducted to study the adsorption, retention and bonding of the scale inhibitor with nanomaterials and rock. NCEST technique was observed to significantly increase the adsorption of EDTA on rock sample treated with nanomaterials with a maximum adsorption of 180 mg/g compared to 51 mg/g on rock sample without nanomaterials treatment. In terms of cost–benefit, it is estimated to have significant reduction in operating expenses (up to 50%) after implementing the NCEST technique compared to that of conventional squeeze treatment.
Highlights
The formation of mineral scale associated with production of hydrocarbon has been a major strain in oilfield operation
The purpose of this paper is to explore other applications of nanomaterials such as graphene oxide (GO) which have a similar characteristic as carbon nanotubes (CNTs) in improving the scale inhibitor squeeze treatment lifetime
From the result of POROPERM analysis, the pore volume for each core plugs was known. This is useful in preparing the solution to be injected in the coreflooding test as the unit used in terms of pore volume (PV)
Summary
The formation of mineral scale associated with production of hydrocarbon has been a major strain in oilfield operation. The limitation of current scale inhibitor used is the precipitation of acid phosphonate near the entrance of formation results in limited reservoir protection distance. Apart from that, during the precipitation squeeze, only little or negligible amount of phosphonate inhibitor can be retained and slowly released from the formation. This results in a large fraction of the inhibitor flowing back within a few days, leaving an extremely low value in the reservoir that is not sufficient for effective scale inhibition (Shen et al 2008). Numerous studies have been carried out to enhance the adsorption level of inhibitor onto the formation to ensure a successful and effective scale inhibition treatment in the oilfields
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